What is the difference between a servo motor and a stepper motor

Update:08 Dec 2020

The difference between stepper motor and servo motor is:

1. Different control accuracy;

2. Different control methods: one is open loop control, the other is closed loop control;

3. Different low-frequency characteristics: the stepper motor has low-frequency vibration, and the servo motor runs very smoothly;

4. Different moment frequency characteristics;

5. Different overload capacity;

6. Different operating performance;

It can be seen from the above that AC servo system is better than stepper motor in performance, so servo motor is more expensive than stepper motor.

Servo motor selection case and question and answer

Q: starting from 0, it can output 200nm at 3000rpm and 80nm at 4000rpm. Is there a servo like this? If not servo, what other motor can meet the requirements?

A: power (kw) = torque * speed / 9550. According to this calculation, you need servo motor power = 200 * 3000 / 9550 = 62.83kw. At present, the power of some synchronous servo motors in the market is basically below 22KW, so it is difficult for you to order the goods. If you require the positioning accuracy is not high, you can consider using vector frequency converter and frequency converter motor to meet the requirements. If you require high precision, you can use special frequency converter and synchronous motor to meet the requirements. Of course, you can also find the so-called asynchronous servo.


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